Here are some tools that will automate the process of adding lyrics to your iTunes songs.
GimmeSomeTune displays information about the current song playing, including a pop-up window displaying the lyrics. This is good to make sure the lyrics download correctly.
Needle Drop is a script that will play through a selected playlist
(or if you select your Library your entire library) and play each song for a selected amount of time.
Now what we want to do is have iTunes run through the whole library
(or just a playlist) and add lyrics to our songs via downloading them from the internet. If you have a broadband connection you'll be ok, if you're on dial-up you may need to have the songs play longer to get the data time to download. It's best to do this overnight with the speakers muted or while you don't need to use the computer.
Once you have both programs installed open GimmeSomeTune. A music note icon will appear in the top menu in the Finder
(by the clock and Spotlight). Click on that and select Preferences. Navigate to the
"Artwork, Lyrics" tab and select the checkbox under Lyrics. Additionally you can enable cover artwork options as well. Now in iTunes, open the library or playlist you want to download lyrics to. Now look at the top menu bar, click the little Scripts Scroll icon
(between Window and Help) and choose
"Needle Drop". A window will pop up asking how many seconds you want a song to play before skipping to the next song. You could set it for 3 seconds, you may want to give each track more time if you have a slow internet connection. Next a window will ask you how far into each song you may want to play. Enter 0
(to start at the beginning) and click OK. That's all.
Now if everything is working correctly your lyrics and artwork will be loaded onto your songs. Now it's not perfect and it won't catch every song but it's better than doing it all manually. To make sure things are going well go back to the Finder and click on the music note icon again, select
"Show GimmeSomeTune Window" to see the song information, or select
"Show Lyrics" to show the lyrics window.